Pot modding lab laser

[Grix]

I want to pot mod the green module in my RGB projector to decrease power, because the color balance is terrible. But there is two small problems..

1. There is two pots on the driver, how do I know which controls the current? Written next to the pots are VR1 and VR2.
2. The screws on the pots are glued in place . How can I remove this glue without damaging the pots?

 

[kiyoukan]

hobby knife and carefully work around it.
you can also try to use a heated one to.

 

[ElektroFreak]

The only easy way to tell which pot is which is to turn them just a little. If you see an immediate change in power, that's your diode pot. If the power doesn't seem to change at all, or if it does change but very slowly, that's your TEC pot. Just turning the pots will break the glue, it's not very strong.

 

[Grix]

How far is just a little? I tried turning both 1,5 way around and saw no real difference

 

[ElektroFreak]

Well, they are multi-turn pots so it might take a few turns to see much of a change. Basically whichever pot makes the biggest change in the least number of turns is the diode pot. An LPM of some sort is pretty important for this task.

 

[Grix]

What the hell.. they both have immediate and strong effect on the power, except that one decreases power when turned clockwise, and one boosts power when turned clockwise..

EDIT: nvm I think I found the right one

 

[ElektroFreak]

hmm, that's a bit odd.I haven't worked on one of these modules specifically, but I've worked on many that are like them. If I had to say, I'd say that whichever turns the power up when turning clockwise is likely your diode pot, but I'm not 100% on that given your experience so far.

 

[Grix]

Yes I think that one was the diode pot after all, but the TEC pot still had a big effect on the output power, I wasn't expecting that.
Thanks for the help (again and again)

 

[HIMNL9]

There was any modulation input, on your labby ?

If so, one of the pot can also be threshold (or gain) of the mod input .....

Are you sure that there are only 2 trimmers ? ..... nothing other, in any part ?

 

[TTerbo]

correct me if i am wrong but couldnt you just place resisters on the output?

 

[ElektroFreak]

There was any modulation input, on your labby ?

If so, one of the pot can also be threshold (or gain) of the mod input .....

Are you sure that there are only 2 trimmers ? ..... nothing other, in any part ?

There is a modulation input, but being such a simple TTL driver I'd imagine that there is no threshold adjustment. But as I said, I could be wrong.. I haven't ever worked on those drivers specifically.